A study in the journal Science in December sounded a dismal note for zoos. Looking at European zoo elephants, researchers concluded that they live half as long as those in protected rangelands in the wild.

The study blamed the stress of removing zoo elephants from their mothers and transporting them. It also cited obesity – an issue the San Diego Zoo has been tackling by placing its elephants on a well-publicized diet.

Zoo officials say the study's methodology was flawed and only looked at Europe. It didn't cause any of the five U.S. zoos with new exhibits in the works to cancel plans.

At the San Diego Zoo's Elephant Odyssey, eight elephants will share three acres, most of which will be an outdoor yard with a 137,000-gallon pool, officials said.

The $45 million exhibit, funded by private donations and a $1 million state grant, is the first major habitat to open at the zoo since the $28.5 million Monkey Trails in 2005.

It will be like moving from a dreary studio apartment to a tricked-out luxury pad for the zoo's three current elephants, grand dames who retired there after careers in the circus and Hollywood.

These gray ladies now share less than a third of an acre in a 46-year-old exhibit. Five Asian elephants will join them from the 1,800-acre Wild Animal Park, where the remaining 11 African elephants will get more room to roam.

The new zoo exhibit will feature other animals, including lions, jaguars and the endangered California Condor in separate enclosures.

Zoo officials want space to accommodate more males, who must be housed separately. They will rotate the range-bred animals into zoos as desired.

The industry is baby-crazy, officials say, because of the declining number of Asian and African elephants – both endangered species in the wild.

Asian elephants have dwindled to between25,000 and 32,000 in their native lands, according to the World Wildlife Fund. African elephants are better off, with about 500,000 in the wild.

Animal welfare activists are not sold on the zoo industry's rangeland projects. PETA and In Defense of Animals activists say they are concerned the public will be misled by the high acreage numbers because elephants won't be given free access to all that land.

Animal activists still advocate vast, private sanctuaries in Tennessee and Northern California, which take elephants retired by zoos, do not foster breeding and do not accept visitors from the general public.

The zoo industry has never embraced such sanctuaries, pointing out that zoos provide more scientific expertise and conduct research. They also say there's a larger value to people being able to peer into the eyes of a zoo animal: It makes them care about that animal's plight in the wild.

Visitors will get the chance for more nose-to-nose contact at the San Diego Zoo's new exhibit.

One notable feature is the “trunk wall,” a 13-to 14-foot wall that's low enough for elephants to reach over and accept treats from guests – under the watchful eye of zookeepers.